Preesure drop

Discussion in 'Plumbing and Central Heating' started by meditek, 7 Feb 2009.

  1. meditek

    meditek

    Joined:
    11 Jan 2008
    Messages:
    23
    Thanks Received:
    0
    Location:
    Yorkshire
    Country:
    United Kingdom
    I have a Worcester greenstar CDI 42 combi boiler.

    It was just been serviced 2 weeks ago and is one year old.

    I am getting a .75 bar drop in pressure between hot (88C) and cool (48C). Is this normal (acceptable) because I do not remember this happening prior to the service?

    Thanks
     
  2. Sponsored Links
  3. Dan Robinson

    Dan Robinson

    Joined:
    1 Jul 2007
    Messages:
    56,034
    Thanks Received:
    9,420
    Location:
    Hertfordshire & London
    Country:
    United Kingdom
    As long as it settles at the same point then it should be OK... Your expansion vessel charge may need checking though as a .75 pressure rise is a little excessive...
     
  4. meditek

    meditek

    Joined:
    11 Jan 2008
    Messages:
    23
    Thanks Received:
    0
    Location:
    Yorkshire
    Country:
    United Kingdom
    Thanks. I had my suspicions about the expansion chamber. I got the same guy (Worcester-Bosch) back again after the service because it wasn't happening before and he claimed the boiler was A1. What, apart from the boiler can cause this discrepency?

    Thanks
     
  5. kevplumb

    kevplumb

    Joined:
    18 May 2004
    Messages:
    23,712
    Thanks Received:
    925
    Location:
    depends where i get sent
    Country:
    United Kingdom
    so why didnt you air them when the guy came to do the service :?:

    or after when you got him back :?:
     
  6. jamestaylor

    jamestaylor

    Joined:
    5 Feb 2009
    Messages:
    15
    Thanks Received:
    0
    Country:
    United Kingdom

    It`s a pressure drop, not a pressure rise as the system cools it will drop. :LOL: :LOL: :LOL: :LOL:
     
  7. Dan Robinson

    Dan Robinson

    Joined:
    1 Jul 2007
    Messages:
    56,034
    Thanks Received:
    9,420
    Location:
    Hertfordshire & London
    Country:
    United Kingdom
    Depends whether your starting point is hot or cold.


    A drop from hot is contraction/cooling and is perfectly normal - as is a slight rise from cold.. A drop from cold would be a leak and not what the OP reported.
     
  8. jamestaylor

    jamestaylor

    Joined:
    5 Feb 2009
    Messages:
    15
    Thanks Received:
    0
    Country:
    United Kingdom
    ;)
     
  9. Dan Robinson

    Dan Robinson

    Joined:
    1 Jul 2007
    Messages:
    56,034
    Thanks Received:
    9,420
    Location:
    Hertfordshire & London
    Country:
    United Kingdom
    and... :?:

    OP is saying the pressure goes down as the boiler cools.

    So, for example.

    When cold the boiler is sitting at 1 bar. It heats up to 88 degrees and the pressure goes to 1.75.

    As the boiler cools again the pressure returns to 1 bar.
     
  10. Sponsored Links
  11. kevplumb

    kevplumb

    Joined:
    18 May 2004
    Messages:
    23,712
    Thanks Received:
    925
    Location:
    depends where i get sent
    Country:
    United Kingdom
  12. Dan Robinson

    Dan Robinson

    Joined:
    1 Jul 2007
    Messages:
    56,034
    Thanks Received:
    9,420
    Location:
    Hertfordshire & London
    Country:
    United Kingdom
    Is it me or is it a wind-up...?
     
  13. jamestaylor

    jamestaylor

    Joined:
    5 Feb 2009
    Messages:
    15
    Thanks Received:
    0
    Country:
    United Kingdom
    Err... he isn`t getting a .75 rise is he ? he`s getting a .75 drop ;) which isn`t spectacular. :rolleyes:
     
  14. kevplumb

    kevplumb

    Joined:
    18 May 2004
    Messages:
    23,712
    Thanks Received:
    925
    Location:
    depends where i get sent
    Country:
    United Kingdom
    ex vessel and prv then cliver
     
  15. jamestaylor

    jamestaylor

    Joined:
    5 Feb 2009
    Messages:
    15
    Thanks Received:
    0
    Country:
    United Kingdom

    if it was ex vessel then the boiler would show it to be over pressurised probably around 3 bar immediately :rolleyes: , if it was the prv then it would indeed be losing pressure via the blow off, easy to check innit....Basically what I am saying is: his boiler is performing exactly the way it should be and there is no problem.. ;)
     
  16. Dan Robinson

    Dan Robinson

    Joined:
    1 Jul 2007
    Messages:
    56,034
    Thanks Received:
    9,420
    Location:
    Hertfordshire & London
    Country:
    United Kingdom
    Not if it was only marginally under pressured.

    Let me know what hospitals you work in, so I can avoid being ill in those areas... ;)
     
  17. swidders

    swidders

    Joined:
    19 Jan 2009
    Messages:
    1,410
    Thanks Received:
    1
    Location:
    Manchester
    Country:
    United Kingdom
    Broadmoor??? :LOL: :LOL:
     
Loading...

Share This Page